Pressure debulking system

ABSTRACT

A pressure debulking system includes a debulking chamber having a debulking chamber interior, a pressure bladder having a bladder interior provided in the debulking chamber interior, a vacuum port disposed in fluid communication with the debulking chamber interior and a pressure port disposed in fluid communication with the debulking chamber interior. A pressure debulking method is also disclosed.

This application is a divisional of application Ser. No. 11/956,793,filed Dec. 14, 2007.

TECHNICAL FIELD

The disclosure relates to debulking of composite layups. Moreparticularly, the disclosure relates to a circumferential pressuredebulking system and method for debulking composite layups.

BACKGROUND

During the course of various fabrication processes, including theaerospace industry for example and without limitation, it may benecessary to debulk composite layups. Conventionally, this may beaccomplished by applying layers of protective film, breather materialand vacuum film over the layup at the fabrication stage which requiresdebulking. Sealant tape may be applied around the periphery of the part,allowing the vacuum film to be completely sealed. A vacuum port may beinstalled through the vacuum film. Shop vacuum may be applied to theassembly, allowing vacuum pressure to squeeze and compact the layup.Other devices known as vacuum debulk boxes may apply vacuum pressurefrom above the layup only.

Conventional methods of debulking composite layups may be time-consumingand laborious. Furthermore, the methods may be required many timesthroughout the layup process and the materials used in the methods maynot be re-used. This may contribute to the overall time and cost of thefabrication process.

Therefore, a circumferential pressure debulking system and method fordebulking composite layups which is expeditious and cost-effective isneeded.

SUMMARY

The disclosure is generally directed to a pressure debulking system. Anillustrative embodiment of the pressure debulking system includes adebulking chamber having a debulking chamber interior, a pressurebladder having a bladder interior provided in the debulking chamberinterior, a vacuum port disposed in fluid communication with thedebulking chamber interior and a pressure port disposed in fluidcommunication with the debulking chamber interior.

The disclosure is further generally directed to a pressure debulkingmethod. An illustrative embodiment of the method includes providing acomposite layup, providing a chamber having a pressure bladder in thechamber, expanding the pressure bladder by inducing a vacuum in thechamber, placing the composite layup in the chamber and applying thepressure bladder against the composite layup by applying pressureagainst the pressure bladder.

BRIEF DESCRIPTION OF THE ILLUSTRATIONS

FIG. 1 is a partially schematic sectional view of an illustrativeembodiment of the pressure debulking system.

FIG. 2 is a partially schematic sectional view of the pressure debulkingsystem, with a composite layup wound on a mandrel and extending into adebulking chamber of the pressure debulking system.

FIG. 3 is a partially schematic sectional view of the pressure debulkingsystem, with the mandrel-wound composite layup extending into thedebulking chamber and a breather string attached to the composite layup.

FIG. 4 is a partially schematic sectional view of the pressure debulkingsystem, with an end plate closing an end of the debulking chamber.

FIG. 5 is a partially schematic sectional view of the pressure debulkingsystem, illustrating application of pressure to a pressure bladder ofthe system and application of the pressure bladder to the compositelayup.

FIG. 6 is a partially schematic sectional view of the pressure debulkingsystem, illustrating debulking of an elongated composite layup.

FIG. 7 is a flow diagram of an illustrative pressure debulking method.

FIG. 8 is a flow diagram of an aircraft production and servicemethodology.

FIG. 9 is a block diagram of an aircraft.

DETAILED DESCRIPTION

The disclosure is generally directed to a circumferential pressuredebulking system and method suitable for debulking composite layups incomposite fabrication processes. The system and method may be applicableto any of a variety of industries including the aerospace industry, forexample and without limitation. The system and method may facilitate theapplication of circumferential pressure to a composite layup to debulkthe composite layup in a manner which is expeditious and cost-effective.

Referring initially to FIG. 1, an illustrative embodiment of thepressure debulking system, hereinafter system, is generally indicated byreference numeral 1. The system 1 may include a debulking chamber 2having a debulking chamber interior 3. A chamber opening 5 (one of whichis shown) may be provided at each end of the debulking chamber 2. Acircumferential chamber end flange 2 a may extend outwardly from thedebulking chamber 2 at each chamber opening 5. A vacuum port 10 and apressure port and regulator 12 having a pressure gauge 13 may bedisposed in fluid communication with the debulking chamber interior 3. Apressure safety valve 16 may also communicate with the debulking chamberinterior 3.

A resilient or elastomeric pressure bladder 6 may be provided in thechamber interior 3 of the debulking chamber 2. The pressure bladder 6may have a bladder interior 7 which is disposed in a fluid-tight sealwith respect to the chamber interior 3. The pressure bladder 6 may alsoinclude an exterior bladder surface 6 a which faces the debulkingchamber interior 3 of the debulking chamber 2 and an interior bladdersurface 6 b which faces the bladder interior 7 of the pressure bladder6. Each end of the pressure bladder 6 may have a bladder mouth 8 (one ofwhich is shown) which communicates with the bladder interior 7. Eachbladder mouth 8 of the pressure bladder 6 may correspond in orientationand position to the corresponding chamber opening 5 at each end of thedebulking chamber 2. The pressure bladder 6 may be attached to thedebulking chamber 2 in a fluid-tight seal according to any suitabletechnique which is known to those skilled in the art. For example andwithout limitation, a bladder anchor slot 4 may be provided in eachchamber end flange 2 a. Each end of the pressure bladder 6 may beanchored in the corresponding bladder anchor slot 4.

Referring next to FIGS. 2-5, in typical application of the system 1, avacuum may be induced in the debulking chamber interior 3 of thedebulking chamber 2, as shown in FIG. 2. This may be accomplished byreleasing gas such as air, for example and without limitation, from thedebulking chamber 2 through the vacuum port 10, as shown in FIG. 2. Thevacuum induced in the debulking chamber interior 3 may expand thepressure bladder 6 and draw the exterior surface 6 a of the pressurebladder 6 against the interior surface of the debulking chamber 2. Thismay provide optimum clearance for insertion of a composite layup 22 intothe bladder interior 7 of the pressure bladder 6.

The composite layup 22 may be inserted into the bladder interior 7 ofthe pressure bladder 6 through the chamber opening 5 of the debulkingchamber 2 and the bladder mouth 8 of the pressure bladder 6. Thecomposite layup 22 may be wound in generally cylindrical form around amandrel 20. The composite layup 22 may be a composite part such as ahat-shaped layup or a round or otherwise-shaped composite tube, forexample and without limitation.

As shown in FIG. 3, a breather string or strip 26 may be applied to thecomposite layup 22. The breather string/strip 26 may extend from thebladder interior 7 of the pressure bladder 6 through the bladder mouth 8and from the debulking chamber interior 3 through the chamber opening 5of the debulking chamber 2.

As shown in FIG. 4, the vacuum in the debulking chamber interior 3 ofthe debulking chamber 2 may be released by terminating flow of the gas34 (FIG. 3) from the debulking chamber interior 3 through the vacuumport 10. This may cause the pressure bladder 6 to relax and the exteriorbladder surface 6 a to disengage the interior surface of the debulkingchamber 2. A chamber end plate 30 may be placed over each chamberopening 5 of the debulking chamber 2. A central plate opening 31 mayextend through the chamber end plate 30. The breather string/strip 26may extend through the plate opening 31.

As shown in FIG. 5, pressure may be applied to the exterior bladdersurface 6 a of the pressure bladder 6 for a selected period of time.Application of pressure to the pressure bladder 6 may be accomplished byintroducing a pressurized gas 36, such as air for example and withoutlimitation, into the debulking chamber interior 3 of the debulkingchamber 2 through the pressure port and regulator 12. Accordingly, thepressurized gas 36 may substantially fill the debulking chamber interior3 and impinge against the exterior surface 6 a of the pressure bladder 6such that the interior bladder surface 6 b of the pressure bladder 6exerts pressure of corresponding magnitude against the composite layup22. Therefore, the pressure bladder 6 may compress and debulk thecomposite layup 22. The magnitude of pressure which is exerted by thepressure bladder 6 against the composite layup 22 may correspond to themagnitude of pressure of the pressurized gas 36. This pressure may beselected by operation of the pressure port and regulator 12 andindicated by the pressure gauge 13 of the pressure port and regulator12.

After a period of time which may be selected according to the debulkingrequirements of the composite layup 22, flow of the pressurized gas 36into the debulking chamber interior 3 may be terminated to release theinterior bladder surface 6 b of the pressure bladder 6 from the exteriorsurface of the composite layup 22. The debulking process may be repeatedas often as necessary based on the particular debulking requirements ofthe composite layup 22. Furthermore, the magnitude of pressure of thepressurized gas 36, and thus the magnitude of pressure of the pressurebladder 6 against the composite layup 22, may be adjusted throughout arange of possible pressures by operation of the pressure port andregulator 12. The pressure bladder 6 may be sized to eliminate wrinklingwhen expanded against the surface of the composite layup 22.

At the end of the debulking process, the composite layup 22 may beremoved from the bladder interior of the pressure bladder 6.Accordingly, a vacuum may again be induced in the debulking chamberinterior 3 to expand and draw the pressure bladder 6 against theinterior surface of the debulking chamber 2 by flowing gas 34 (FIGS. 2and 3) from the debulking chamber interior 3; the chamber end plate 30may be removed from the chamber end flange 2 a; and the mandrel 20 anddebulked composite layup 22 thereon may be removed from the bladderinterior 7 of the pressure bladder 6 through the bladder mouth 8 of thepressure bladder 6 and the chamber opening 5 of the debulking chamber 2.

Referring next to FIG. 6, in some applications it may be necessary todebulk an elongated composite layup 22 the length of which may beincapable of being positioned entirely within the confines of thebladder interior 7 of the pressure bladder 6. Accordingly, a chamber endplate 30 having a plate opening 31 which is sized to accommodate thediameter or width of the composite layup 22 may be placed on the chamberend flange 2 a of the debulking chamber 2. During the debulking process,which may be carried out as was heretofore described with respect toFIGS. 2-5, both the composite layup 22 and the breather string 26 mayprotrude from the debulking chamber 2 through the plate opening 31 ofthe chamber end plate 30.

Referring next to FIG. 7, a flow diagram 700 which illustrates anillustrative pressure debulking method is shown. In block 702, acomposite layup may be provided. In block 704, a pressure bladder in thechamber may be expanded by inducing a vacuum in the chamber. In block706, the composite layup may be inserted in a chamber. In block 708, abreather string may be applied to the composite layup. In block 710, thevacuum in the chamber may be relaxed. In block 712, the ends of thechamber may be closed. In block 714, the pressure bladder may be appliedagainst the composite layup by applying pressure to the chamber. Thecomposite layup may be removed from the chamber by reversing the stepsin blocks 704-714.

Referring next to FIGS. 8 and 9, embodiments of the disclosure may beused in the context of an aircraft manufacturing and service method 78as shown in FIG. 8 and an aircraft 94 as shown in FIG. 9. Duringpre-production, exemplary method 78 may include specification and design80 of the aircraft 94 and material procurement 82. During production,component and subassembly manufacturing 84 and system integration 86 ofthe aircraft 94 takes place. Thereafter, the aircraft 94 may go throughcertification and delivery 88 in order to be placed in service 90. Whilein service by a customer, the aircraft 94 may be scheduled for routinemaintenance and service 92 (which may also include modification,reconfiguration, refurbishment, and so on).

Each of the processes of method 78 may be performed or carried out by asystem integrator, a third party, and/or an operator (e.g., a customer).For the purposes of this description, a system integrator may includewithout limitation any number of aircraft manufacturers and major-systemsubcontractors; a third party may include without limitation any numberof vendors, subcontractors, and suppliers; and an operator may be anairline, leasing company, military entity, service organization, and soon.

As shown in FIG. 9, the aircraft 94 produced by exemplary method 78 mayinclude an airframe 98 with a plurality of systems 96 and an interior100. Examples of high-level systems 96 include one or more of apropulsion system 102, an electrical system 104, a hydraulic system 106,and an environmental system 108. Any number of other systems may beincluded. Although an aerospace example is shown, the principles of theinvention may be applied to other industries, such as the automotiveindustry.

The apparatus embodied herein may be employed during any one or more ofthe stages of the production and service method 78. For example,components or subassemblies corresponding to production process 84 maybe fabricated or manufactured in a manner similar to components orsubassemblies produced while the aircraft 94 is in service. Also, one ormore apparatus embodiments may be utilized during the production stages84 and 86, for example, by substantially expediting assembly of orreducing the cost of an aircraft 94. Similarly, one or more apparatusembodiments may be utilized while the aircraft 94 is in service, forexample and without limitation, to maintenance and service 92.

Although the embodiments of this disclosure have been described withrespect to certain exemplary embodiments, it is to be understood thatthe specific embodiments are for purposes of illustration and notlimitation, as other variations will occur to those of skill in the art.

What is claimed is:
 1. A pressure debulking system, comprising: adebulking chamber having a debulking chamber interior that comprises achamber opening that communicates with the debulking chamber interiorthat comprises a pressure bladder that comprises a bladder interior,such that the pressure bladder comprises an expanded position and arelaxed position; a vacuum port disposed in fluid communication withsaid debulking chamber interior, the vacuum port configured to receive avacuum between the pressure bladder and the chamber such that thepressure bladder, in the expanded position, contacts an interior surfaceof the debulking chamber, and the vacuum port configured to release thevacuum such that the pressure bladder, in the relaxed position, beingdisengaged from the interior surface of the debulking chamber; apressure port disposed in fluid communication with said debulkingchamber interior, the pressure port configured to apply gas pressure tothe pressure bladder such that when gas presses against the pressurebladder, an interior surface of the pressure bladder to encircles andpresses against a mandrel positioned in the debulking chamber interiorand within the pressure bladder; and an end plate positioned on thedebulking chamber, such that the end plate comprises a central openingthat comprises a size and shape such that the bladder remains inside thedebulking chamber interior and allows a first portion of the mandrel topass through the central opening and extend outside of the chamber whilea second portion of the mandrel remains inside the chamber as thebladder encircles and maintains a compression on the second portion ofthe mandrel.
 2. The system of claim 1 further comprising a pressuresafety valve disposed in fluid communication with said debulking chamberinterior.
 3. The system of claim 1 further comprising a pressure gaugeprovided on said pressure port.
 4. The system of claim 1 furthercomprising a chamber end flange provided on said debulking chamber atthe chamber opening.
 5. The system of claim 4 further comprising abladder anchor slot provided in said chamber end flange and wherein saidpressure bladder is anchored in said bladder anchor slot.
 6. The systemof claim 1 further comprising a breather string that communicates withsaid debulking chamber and extends through the chamber opening.
 7. Apressure debulking system that comprises: a debulking chamber thatcomprises a debulking chamber interior and at least one chamber openingthat communicates with said debulking chamber interior; a pressurebladder that comprises: a bladder interior provided in said debulkingchamber interior, and at least one bladder mouth that communicates withsaid bladder interior at said at least one chamber opening, such thatthe pressure bladder comprises an expanded position and a relaxedposition; a vacuum port disposed in fluid communication with saiddebulking chamber interior, the vacuum port configured to receive avacuum between the pressure bladder and the chamber such that thepressure bladder, in the expanded position, contacts an interior surfaceof the debulking chamber, and the vacuum port configured to release thevacuum such that the pressure bladder, in the relaxed position, beingdisengaged from the interior surface of the debulking chamber; apressure port disposed in fluid communication with said debulkingchamber interior, the pressure port configured to apply gas pressure tothe pressure bladder such that when gas presses against the pressurebladder, an interior surface of the pressure bladder encircles andpresses against a mandrel positioned in the debulking chamber interiorand within the pressure bladder; and an end plate positioned on thedebulking chamber, such that the end plate comprises a central openingthat comprises a size and shape such that the bladder remains inside thedebulking chamber interior and allows a first portion of the mandrel topass through the central opening and extend outside of the chamber whilea second portion of the mandrel remains inside the chamber as thebladder encircles and maintains a compression on the second portion ofthe mandrel.
 8. The system of claim 7 further comprising a pressuresafety valve disposed in fluid communication with said debulking chamberinterior.
 9. The system of claim 7 further comprising a pressure gaugeprovided on said pressure port.
 10. The system of claim 7 furthercomprising a chamber end flange provided on said debulking chamber atsaid at least one chamber opening.
 11. The system of claim 10 furthercomprising a bladder anchor slot provided in said chamber end flange andwherein said pressure bladder is anchored in said bladder anchor slot.12. The system of claim 7 further comprising a chamber end plateprovided on said debulking chamber at said at least one chamber opening.13. The system of claim 7 further comprising a breather stringcommunicating with said debulking chamber and extending from said atleast one chamber opening.
 14. A pressure debulking system for debulkingcomposite materials, comprising: a debulking chamber that comprises adebulking chamber interior and at least one chamber opening thatcommunicates with said debulking chamber interior; a pressure bladderthat comprises: a bladder interior provided in said debulking chamberinterior, and at least one bladder mouth that communicates with saidbladder interior at said at least one chamber opening, such that thepressure bladder comprises an expanded position and a relaxed position;a vacuum port disposed in fluid communication with said debulkingchamber interior, the vacuum port configured to receive a vacuum betweenthe pressure bladder and the chamber such that the pressure bladder, inthe expanded position, contacts an interior surface of the debulkingchamber, and the vacuum port configured to release the vacuum such thatthe pressure bladder, in the relaxed position, being disengaged from theinterior surface of the debulking chamber; a pressure port disposed influid communication with said debulking chamber interior, the pressureport configured to apply gas pressure to the pressure bladder such thatwhen gas presses against the pressure bladder, an interior surface ofthe pressure bladder encircles and presses against a mandrel positionedin the debulking chamber interior, the mandrel being cylindrical; and anend plate sealing the chamber opening, wherein a composite layup ispositioned on the mandrel, and the end plate is separate from themandrel, such that the end plate comprises a central opening thatcomprises a size and shape such that the bladder remains inside thedebulking chamber interior and allows a first portion of the mandrel anda breather string to pass through the central opening and extend outsideof the chamber while a second portion of the mandrel remains inside thechamber as the bladder encircles and maintains a compression on thesecond portion of the mandrel.
 15. The pressure debulking system ofclaim 14 further comprising the breather string extending from thecomposite layup through the end plate to an exterior of the chamber.